Embodiments of the present invention exemplarily described herein relate generally to apertures formed in substrates and methods of forming the same. More particularly, embodiments of the present invention relate to methods of processing laser-machined features.
It is generally known that many semiconductor manufacturing applications require the use of “through-silicon vias.” Typically, a through-silicon via or (TSV) is a vertical channel extending through a silicon substrate, which can be coated or filled with a conductive material to allow electrical current or heat to flow from one side of the substrate to the other. TSVs can be formed by various methods. For example, TSVs can be formed in a dry etch process in which reactive gases etch the substrate under vacuum. However dry etch processes can produce TSVs with sidewalls having an undesirably scalloped surface profile. To avoid the scalloped surface profile, the dry etch process is typically slowed significantly or the TSV is subjected to additional processing (e.g., coating and etching processes). TSVs can also be formed using lasers in which a laser beam heats and ablates the substrate. However, laser drilling typically produces TSVs having sidewalls with non-uniform composition and crystalline structure, and an undesirably rough surface profile. A number of processes, which include dry etching processes and wet etching processes, have been proposed to address the deleterious effects caused by laser drilling. Such processes have limited benefit, however, because they do not produce TSVs with many desirable characteristics (e.g., adequately smooth sidewalls and controllable aspect ratio, taper, entrance diameter, exit diameter and cross-sectional profile).